1. Declare your arrival in Luxembourg

These are the priority formalities to be completed upon your arrival in Luxembourg:
If you are from an EU country, you must present:

A valid identity card or passport (accompanied, if possible, by the required visa or a residence permit issued by another EU country)
Your family book if you have one, or your marriage certificate and the birth certificates of your children
It may be that other papers are requested, you'll find further advice by contacting the competent local authority or on www.guichet.lu

If you are coming from a country outside of the EU zone:

You must file a registration statement as a citizen of the European Union or of an assimilated country! The registration form is available on guichet.lu
Check with the Luxembourg Embassy in your country or verify at the Ministry of Foreign Affairs of Luxembourg what papers exactly you’ll have to introduce.
And above all, make sure your ID papers are valid (identity card or passport according to your country of origin) and secure yourself a visa or a residence permit prior to your arrival
Your family book if you have one, or your marriage certificate and the birth certificates of your children

Moving to Luxembourg, the key steps to follow